In manufacturing semiconductor devices such as LSI and super-LSI or in manufacturing a liquid crystal display board or the like, a pattern is made by irradiating light to a semiconductor wafer or an exposure original plate (a mask for lithography) for liquid crystal, but if a dust adheres to the exposure original plate, the dust absorbs light or refracts it, causing deformation of a transferred pattern, roughened edges or black stains on a base, and leads to a problem of damaged dimensions, poor quality, deformed appearance and the like.
Thus, these works are usually performed in a clean room, but, even in a clean room, it is still difficult to keep the exposure original plate clean all the time. Therefore, a pellicle, through which the light for exposure passes well, is attached to a surface of the exposure original plate as a dust-fender.
Under such circumstances, foreign substances do not directly adhere to the surface of the exposure original plate, but only onto the pellicle membrane, which is sufficiently removed from the surface of the exposure original plate, and thus by setting a photo focus on a lithography pattern on the exposure original plate, the foreign to substances on the pellicle membrane fail to transfer their shadows on the exposure original plate and thus no longer become a problem to the image transfer performance.
In general, a pellicle is built up of a pellicle frame, which is an endless frame bar usually made of a black almite-anodized aluminum alloy such as JIS A7075, A6061 and A5052, or a stainless steel or polyethylene, and a transparent pellicle membrane usually made of cellulose nitrate, cellulose acetate or a fluorine-containing polymer; this membrane is attached to one of the two frame faces (hereinafter referred to as “upper frame face”) after laying a solvent capable of dissolving the pellicle membrane on the upper frame face and drying the solvent by air flow (ref. Publication-in-patent 1), or after laying an adhesive such as acrylic resin, epoxy resin and fluorine-containing resin (ref. Publications-in-patent 2 and 3); furthermore, on the other one of the two frame faces (hereinafter referred to as “lower frame face”) is laid a mask-bonding adhesive layer made of a polybutene resin, a polyvinyl acetate resin, an acrylic resin, a silicone resin or the like for attaching the pellicle frame to the exposure original plate, such as a reticle or a mask, and over this mask-bonding adhesive layer is laid a releasable liner for protecting the mask-bonding adhesive layer. FIGS. 1 and 2 show a construction of a general type pellicle.